diff --git a/clang/lib/Headers/hlsl/hlsl_intrinsics.h b/clang/lib/Headers/hlsl/hlsl_intrinsics.h
--- a/clang/lib/Headers/hlsl/hlsl_intrinsics.h
+++ b/clang/lib/Headers/hlsl/hlsl_intrinsics.h
@@ -15,9 +15,6 @@
 
 __attribute__((clang_builtin_alias(__builtin_acos))) double acos(double In);
 __attribute__((clang_builtin_alias(__builtin_acosf))) float acos(float In);
-__attribute__((clang_builtin_alias(__builtin_acosl))) long double acos(long double In);
-//__attribute__((clang_builtin_alias(__builtin_acosf128))) __float128 acos(__float128 In);
-
 
 
 #endif //_HLSL_HLSL_INTRINSICS_H_
diff --git a/clang/test/CodeGenHLSL/builtins/acos.hlsl b/clang/test/CodeGenHLSL/builtins/acos.hlsl
--- a/clang/test/CodeGenHLSL/builtins/acos.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/acos.hlsl
@@ -17,18 +17,3 @@
 
 // CHECK: define noundef float @"?acos_f@@YAMM@Z"(
 // CHECK: call noundef float @acosf(float noundef %0)
-
-long double acos_ld(long double x)
-{
-  return acos(x);
-}
-
-// CHECK: define noundef double @"?acos_ld@@YAOO@Z"(
-// CHECK: call noundef double @acosl(double noundef %0)
-
-/*
-long long double acos_lld(long long double x)
-{
-  return acos(x);
-}
-*/
\ No newline at end of file